2.1 Study population
This retrospective observational study enrolled patients who underwent conventional RVP (n=200) or LBBAP (n=65) performed by operators without previous LBBAP experience between December 2020 and October 2021 at Yonsei University Severance Hospital in the Republic of Korea. All patients who required ventricular lead implantation during this period were included. For the learning curve analysis, patients who underwent dual-chamber pacemaker implantation by a single experienced operator were divided into a group that underwent conventional RVP (n=65) and a group that underwent LBBAP (n=50) (Figure 1). This study was followed the ethical rules of the Declaration of Helsinki (2013) of the World Medical Association, and approved by the Institutional Review Board of Yonsei University Health System. Following strict confidentiality guidelines, personally identifiable information were removed after the database was created and therefore exempt from prior consent requirements.